Question

At which point is the electric field intensity due to an electric dipole (a) parallel and (b) antiparallel to the electric dipole moment of the dipole?

Answer 1

Explanation:

Work done by external agent in rotating the dipole 

W=PE[cosθ1−cosθ2]

Consider the initial angle to be

θ1=0 

and the final angle will be

 θ2=180o

So,⇒ W=PE[cos 0o−cos 180o]=2PE